1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a technology effectively used when applied to a liquid crystal display device included in a display unit of a portable device.
2. Background Art
Currently, a TFT (thin film transistor) system liquid crystal display device has been widely used as a display device of a personal computer, TV, and other apparatus. This liquid crystal display device has a liquid crystal display panel and a driver circuit for driving the liquid crystal display panel.
Also, a number of miniaturized liquid crystal display device of this type has been increasing as a display unit of a portable device such as a cellular phone. In case of the liquid crystal display device as the display unit of the portable device, the power consumption of the liquid crystal display device is preferably smaller than that of a conventional type of liquid crystal display device.
JP-A-5-224626 discloses a technology which includes a common gate driver for supplying common voltage to a liquid crystal panel and supplies common voltage to respective scanning signal lines. However, this reference does not show how to control the common voltage.